The research objectives of this renewal application are to continue and extend studies in ocular pharmacology that the chief investigator and his associates have engaged in under the previous support of this grant. The areas to be explored include: 1. The penetration and distribution (systemic and ocular) of ophthalmic drugs. 2. The mechanism of action of pharmacologic agents. 3. The testing of new agents for efficacy and toxicity in animals. 4. The mechanisms of toxicity of therapeutic agents. 5. The establishment of animal model systems for drug studies and for the investigation of human ocular conditions. 6. The investigation of laboratory tests for clinical diagnostic purposes in human ocular disease.